refactor(bar): modularize bar widgets and layout

modules/bar/SystemTrayWidget.qml

@@ -0,0 +1,36 @@
+pragma ComponentBehavior: Bound
+
+import QtQuick
+import Quickshell.Services.SystemTray
+import qs.config
+
+Rectangle {
+  id: root
+
+  property int iconSize: 16
+
+  implicitWidth: trayRow.implicitWidth + 10
+  implicitHeight: 34
+  radius: Appearance.radius
+  color: Appearance.colors.inActive
+  visible: SystemTray.items.values.length > 0
+
+  Row {
+    id: trayRow
+
+    anchors.centerIn: parent
+    spacing: Appearance.spacing
+
+    Repeater {
+      model: SystemTray.items.values
+
+      Image {
+        required property var modelData
+
+        source: modelData.icon
+        width: root.iconSize
+        height: root.iconSize
+      }
+    }
+  }
+}